Known vehicle suspension systems include an active body control system (ABC Module) having a damping portion and having a mechanical spring portion. The damping portion includes a damping cylinder and a damping valve of fixed damping characteristics. The position of the spring seat of the mechanical spring portion is hydraulically controlled only at low frequencies below the wheel hop frequency using a hydraulically actuated plunger, a proportional valve, an accumulator, and a pump.
What is needed is an improved vehicle suspension system having a mechanical spring portion and an improved method for operating a vehicle suspension system having a mechanical spring portion.